Periodontitis and blood pressureexploring the association

Resumen

Background: Recent evidence suggests a link between periodontitis and hypertension; however, the nature and magnitude of the association are yet to be determined. The aim of this PhD was to further our understanding of this relationship. Material & Methods: To investigate the research hypothesis, three studies were conducted. A robust systematic review (part 1) intended to ascertain whether patients with periodontitis were more likely to have hypertension when compared to those without periodontitis. Secondary objectives evaluated i: linear relationship between periodontitis (extent/severity) and hypertension [measures of blood pressure (BP)], ii: the mean BP values in periodontitis versus non-periodontitis and iii: the effect of periodontal therapy on systolic (SBP) and diastolic blood pressure (DBP). A cross-sectional analysis (part 2) of two well-established surveys of representative samples of USA and Korean populations was designed with to further assess, i: the degree of association between periodontitis and hypertension, ii: the potential role of systemic inflammation in mediating this association. A post-hoc nested case-control study (part 3) in a sample of systemically healthy participants with the objective to investigate i: the association between periodontitis and mean BP levels, ii: the relationship with systemic inflammatory makers and its mediation effect, iii: the level of possible undetected hypertension in the sample population. Results: The systematic review included 81 studies (comprising observational and interventional designs). Moderate-severe periodontitis (OR = 1.22; 95% CI: 1.10–1.35, P=0.0001) and severe periodontitis (OR = 1.49; 95% CI: 1.09–2.05, P=0.01) were associated with hypertension. Diagnosis of periodontitis increased the likelihood of hypertension in prospective studies (OR = 1.68; 95% CI: 0.85–3.35, P=0.14). Further, participants with periodontitis exhibited higher mean SBP (WMD = 4.49 mmHg; 95% CI: 2.88–6.11, P=0.00001) and DBP (WMD = 2.03 mmHg; 95% CI: 1.25–2.81, P=0.00001) when compared to controls. Less than half (5 out of 12) of interventional studies confirmed a reduction in BP following the treatment of periodontitis, ranging from an average of 3-12.5 mm Hg of SBP and from 0-10 mm Hg of DBP. The cross-sectional study results confirmed that participants with periodontitis had increased odds of hypertension (NHANES: OR = 1.3, 95% CI: 1.0–1.6, P=0.025; KNHANES: OR = 1.2, 95% CI: 1.0–1.4, P=0.041) and actual SBP≥140 mmHg (NHANES: OR = 1.6, 95% CI: 1.1–2.3, P<0.001; KNHANES: OR = 1.3, 95% CI: 1.0– 1.6, P<0.031) following adjustment of traditional confounders and confirmed in participants not taking antihypertensive medications. Diagnosis of periodontitis was directly associated with WBC in both surveys and with CRP levels in the NHANES. Mediation analyses confirmed that CRP acted as a mediator in the association between periodontitis and hypertension in both populations. WBC acted as a mediator in the KNHANES whilst in the NHANES, its effect was dependent of CRP inclusion in the model. Lastly, from the nested case-control study cases (participants with severe periodontitis) presented with 3.36 mm Hg (95% CI, 0.91–5.82, P=0.007) higher mean SBP and 2.16 mm Hg (95% CI, 0.24–4.08, P=0.027) higher DBP than controls (without periodontitis). Diagnosis of periodontitis was associated with mean SBP (β=3.46±1.25, P=0.005) and greater odds of SBP≥140 mmHg (OR = 2.3, 95% CI, 1.15–4.60, P=0.018) independent of common cardiovascular risk factors. Similar findings were observed when continuous measures of periodontal status were modelled against SBP. Measures of systemic inflammation although elevated in periodontitis were not found to be mediators of the association between periodontitis and arterial BP values in this sample of participants without hypertension. Conclusions: Diagnosis of periodontitis is consistently associated with increased odds of hypertension, higher SBP/DBP levels and systemic inflammatory biomarkers. Patientcentred approaches integrating both the medical and dental communities will be crucial in the prevention and management not only of periodontitis but also hypertension and its complications.